Conventional devices for measuring flow of granular products such as the traveling belt and the rotating star valve have many limitations and undesirable operating features. A traveling belt device is difficult to install in an existing arrangement of industrial storage and conveyance equipment. Rotating star valves can measure and meter flows of granular products but they are limited in rotational speed as they depend upon the free-flowing characteristics of a product to fill the empty chambers of the valve as they present themselves one at a time to a product.
As granular material flows through a closed conduit in which this invention is installed, the twisted flat plate of the apparatus is caused to rotate in a screw action at a rate directly proportional to the volumetric flow of the material. This rotation is communicated outside the confines of the conduit either mechanically, electronically, or both, for accumulative flow record keeping. Each revolution of the helix shaped device will represent a certain volume of product as determined by measured discharge calibration.
It is vitally important to continuously and directly monitor the rate of flow of some granular materials. Measuring crushed coal going into the firebox of a steam boiler is necessary so that the energy consumption efficiency can be constantly maintained as high as possible. A direct measurement of the energy input to a steam boiler is much preferred to calculating the energy input indirectly by exhaust gas analysis. Constantly monitoring the flow of certain products such as wheat and mined coal at many locations in a long conveyance system is advantageous to alert operators of equipment failure, pilferage and the amount of inventory in transit.